1. Field of the Invention
The invention relates to a method for eliminating vertical position-jitter of a second information (Oi) displayed on a display device on which a first information (I) is displayed, the first information (I) determining an addressing of the display device, the method comprising the steps of generating vertical start pulses (V) and horizontal start pulses (H) to control vertical start positions of fields of the first information (I) and horizontal start positions of lines of the first information (I), respectively, on the display device; and counting a predetermined number of the horizontal start pulses (H), to define a vertical start position for a display of the second information (Oi) on the display device.
The invention also relates to a vertical position-jitter elimination circuit for eliminating jitter in a vertical position of a second information (Oi) displayed on a display device on which a first information (I) is displayed, the first information (I) determining an addressing of the display device, the circuit comprising a processing circuit coupled to receive the first information (I), for generating vertical (V) and horizontal (H) start pulses to control vertical start positions of fields of lines, and horizontal start positions of the lines, respectively, of the first information (I) on the display device; timing means for supplying a vertical position signal (Vp), defining a vertical starting position on the display of the second information (Oi), by counting a predetermined number of the horizontal start pulses (H); and an on-screen-display circuit coupled to receive said vertical position signal (Vp) for inserting a display of said second information (Oi) on said display device.
The invention also relates to a picture display apparatus containing such a vertical position-jitter elimination circuit.
The invention also relates to a method for eliminating vertical position-jitter of a second information (Oi) displayed on a display device on which a first information (I) is displayed, the first information (I) determining an addressing of the display device, the method comprising the steps of generating vertical start pulses (V) and horizontal start pulses (H) to control vertical start positions of fields of the first information (I) and horizontal start positions of lines of the first information (I), respectively, on the display device.
The invention is relevant for eliminating jitter in a vertical position of a second information displayed on a display screen, wherein a first information determines the addressing of the display screen. The first information may be a television image, and the second information may be a PIP image, Teletext, or an On-Screen Display (OSD) information.
2. Description of the Related Art
Such a vertical position-jitter elimination circuit is known from Japanese Patent Application JP-A-3-236092. In the known vertical position-jitter elimination circuit, a first information is displayed on a display screen. Vertical and horizontal positions of the first information on the display screen are determined by a moment of occurrence of, respectively, vertical and horizontal start pulses, and both start pulses are extracted from the first information (and in this case being vertical and horizontal flyback pulses). In every field of the first information (I), a vertical starting position of a second information is determined by counting a certain number of the horizontal start pulses after a leading edge of the vertical start pulse. In this case, the second information is an On-Screen Display (OSD) information.
A drawback of the known vertical position-jitter elimination circuit is that in certain situations, a vertical jitter of the second information occurs.